The invention generally relates to fine synchronization of timing for a receiving system especially for systems operating at very low signal-to-noise ratios with the potential for Doppler shift. Such receiving systems may be used in applications including, but not limited to, spread-spectrum communication systems and radar applications.
Such systems may require a receiver to operate at extremely low signal-to-noise ratio (SNR), often, for example, well below negative 20 dB.
Often critical to such operation is the capability of a receiver to synchronize the timing of the signal and accurately measure the shift in timing of the signal caused by Doppler. At an extremely low signal-to-noise ratio, many known symbols must be received to establish very fine timing. The larger the number of known symbols that are received, the greater the amount of drift caused by error in the initial Doppler measurement.
Accordingly, there is a need for a method of fine synchronization of timing for a receiving system especially in contexts in which very low signal to noise ratios are used. There is also a need for a method for performing a fine synchronization of timing, including Doppler shift, while efficiently maintaining throughput by limiting the number of required known symbols.
The techniques herein below extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above-mentioned needs.